This invention relates generally to surgical tools and, more specifically, to a surgical needle with a hand-actuable lock mechanism for holding one part of the needle approximately fixed relative to another part. One embodiment of the needle includes a hollow needle through which a push rod slides, and the lock is used to hold the push rod fixed relative to the hollow needle. Such hollow needle/push rod assemblies often are used when depositing, sampling or removing material within living tissue.
The lock mechanism of the present invention may be mounted on various types of needles, push rods, catheters, stents, trocars, cannulas, wires and stylets. The detailed description of the invention, below, is based on an embodiment that may be used in prostate brachytherapy, in which radioactive seeds are implanted in a human prostate while the needle and seeds are monitored by ultrasound sensors and imaging devices. U.S. Pat. Nos. 4,461,280, 4,700,692 and 4,815,449, the disclosures of which are incorporated herein by reference, disclose background information about the deposition of radioactive seeds within human tissue.
The lock mechanism may be used with other known surgical tools, such as trocar and cannula assemblies, in which an inner member such as a rod or inner hollow needle slidingly fits within and extends through an outer hollow needle to block or interact with an open end of the outer needle. For example, fluid and tissue samples may be taken from a specific part of the body by penetrating the desired part of the body with the end of a needle, and then removing a rod from within the needle to open a hollow cavity in the needle and admit fluid or tissue. A syringe or other injection device may also or alternatively be attached to the needle if fluids or solids are to be injected. Examples of such tools are found in U.S. Pat. Nos. 5,207,647, 5,242,427, 5,290,304, 5,368,046, and 5,556,411, the disclosures of which are incorporated herein by reference.